Nudi Pixel: Nudibranchs and Sea Slugs Identification with Photographs

Comment from Scott Johnson: Well....maybe. Certainly the majority would probably call this Hexabranchus sanguineus, and a paper by Angel Valdes (Valdes, A. 2002. How many species of Hexabranchus (Opisthobranchia: Dorididae) are there? Molluscan Research 22:289-301) suggests that all the forms of Hexabranchus across the Indo-Pacific are all H. sanguineus. However, I have seen a lot of specimens in Hawaii and I'm convinced that there are two species there in any case. (And there could even be others in other parts of the Indo-Pacific--see http://www.seaslugsofhawaii.com/general/Hexabranchus-article.html). If there are indeed two species in Hawaii, the one pictured here would probably be Hexabranchus aureomarginatus Ostergaard, 1955. Confirming that might require more detailed anatomical and DNA analysis.